Simple approach smoke estimation model

Abstract To compare fire emissions against Wyoming Ambient Air Quality Standards for particulates and predict reductions in visual range at selected receptors for public nuisance evaluation, a simple, automated, smoke management tool for prescribed burns was devised. This tool, the Simple Approach Smoke Estimation Model (SASEM), had as its design objectives: 1. (1) minimal data requirements, 2. (2) limited computer resource requirements and 3. (3) easy application by fire management field personnel. SASEM calculates emissions from fire line intensity, average fuel loading and the type of fuel which is burned. Plume rise is calculated from the fuel type (which is used to determine fire front heat production), wind speed and stability. The particulate concentrations are obtained from the emission rate, plume rise, wind speed and stability using the Gaussian dispersion formula for a line source (or point sources in the case of slash piles). The model determines the maximum concentration and if any, the distance range over which applicable standards might be violated. Reduction in visual range at selected receptors is obtained from calculation of a simple scattering coefficient based on particulate concentration at the receptor. The concentration used is from the plume calculations or a simple ‘box model’ type calculation. SASEM has been shown to produce results comparable to other currently available dispersion models suitable for use in prescribed burning studies and used successfully as a smoke management planning and permitting tool in Wyoming by Federal and State authorities.